Halogen-free flame retardant polyamide composition with improved electrical and flammability properties

ABSTRACT

Flame retardant polyamide compositions are provided containing a polyamide; a flame retardant system including a metal phosphinate or diphosphinate salt and a nitrogen compound; an aromatic polymer, and optionallly untreated nanoclay having an aspect ratio of about 100 to about 1000.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefits of U.S. Provisional PatentApplication Ser. No. 60/567851 filed May 4, 2004, which is fullyincorporated herein by reference.

BACKGROUND OF INVENTION

Polymeric materials used for electrical applications are required tomeet stringent industry standards for flame retardant properties, goodarc tracking resistance, while at the same time exhibiting goodmechanical properties, such as tensile modulus and tensile strength.Increasingly stringent requirements also include meeting or exceedingsuch standards as the International Electrotechnical Commission (IEC)Glow Wire Flammability Index (GWFI) or Underwriters Laboratories, Inc.UL-94 flammability class rating.

Polyamide resins provide outstanding heat resistance and moldworkability, making it useful for a variety of applications. However,polyamide shows poor flame resistance, rendering it necessary for theaddition of flame retardants to provide the desired flame retardancydemanded by the particular application. Halogenated compounds andantimony compounds can provide a method to achieve flame retardancy inpolyamide compositions. However the presence of bromine and antimonylimit their application in the electrical and electronics segment, aswell as appliances and transportations. Brominated flame retardantsespecially raise environmental concerns when the composition is burned.

Known, commercially available glass-reinforced halogen-free flameretardant polyamide materials cannot meet all the industry requirements.For instance, such materials fail to meet UL-94 V0 classification. U.S.Pat. No. 6,365,071 discloses a synergistic flame protection agentcombination for thermoplastic polymers, especially for polyesters,containing as component A phosphinic acid salt, a diphosphinic acidsalt, as component B a nitrogen compound including, for example,triazine based compounds, cyanurate based compounds, allantoin basedcompounds, glycoluril based compounds, benzoguanamine based compounds,and the like. U.S. Patent Application 2004/0021135A1 discloses ahalogen-free, flame retarder composition for use in a thermoplasticcomposition, in particular a glass fiber-reinforced polyamidecomposition, which flame retarder composition contains at least 10-90mass percent phosphinate compound, 90-10 mass percent polyphosphate saltof a 1,3,5-triazine compound, and 0-30 mass % olefin copolymer. U.S.Patent Application No. 2004/0225040 discloses a flame retardantnanofilled combination of a thermoplastic polymer, a phosphinic salt, adiphosphinic salt, and an organic intercalated phyllosilicates.

There remains a need for halogen-free flame retardant polyamidecompositions that exhibit good flame retardant properties, excellent arctracking resistance properties, while at the same time retaining goodmechanical properties.

BRIEF DESCRIPTION OF THE INVENTION

The invention relates to a fiber reinforced flame-retardant polyamidecomposition having a combination of good flame retardant properties,good electrical performance such as arc tracking resistance, and goodmechanical properties.

In one embodiment, the flame-retardant composition comprises apolyamide; about 5 to about 25 weight percent of a flame retardantsystem comprising i) a metal phosphinate or diphosphinate salt; and ii)at least one nitrogen compound selected from the group consisting ofcondensation products of melamine and/or reaction products ofcondensation products of melamine with phosphoric acid, and/or mixturesthereof, including for example melam, melem, melon, melamine cyanurate,melamine phosphate compounds, dimelamine phosphate and/or melaminepyrophosphate, benzoguanamine compounds, terepthalic ester compounds oftris(hydroxyethyl)isocyanurate, allantoin compounds, glycolurilcompounds, ammeline, ammelide, and combinations thereof; and about 1 toabout 50 weight percent of at least one aromatic polymer selected fromthe group consisting of poly(arylene ether), polyetherimide,polyetherimide/polyimide copolymers, poly(arylene sulfide), polysulfone,polyethersulfone, polyetheretherketone, an styrenic impact modifier, andcombinations thereof; wherein all the amounts are based upon the totalweight of the composition.

In another embodiment, a flame-retardant composition comprises apolyamide; about 5 to about 25 weight percent of a flame retardantsystem comprising i) a metal phosphinate or diphosphinate salt; and ii)at least one nitrogen compound selected from the group consisting ofcondensation products of melamine and/or reaction products ofcondensation products of melamine with phosphoric acid, and/or mixturesthereof, including for example melam, melem, melon, melamine cyanurate,melamine phosphate compounds, dimelamine phosphate and/or melaminepyrophosphate, benzoguanamine compounds, tereptlialic ester compounds oftris(hydroxyethyl)isocyanurate, allantoin compounds, glycolurilcompounds, ammeline, ammelide, and combinations thereof; and about 2.5to about 40 weight percent of poly(arylene ether) or polyetherimide;wherein all the amounts are based upon the total weight of thecomposition.

In yet another embodiment of either of the flame-retardant compositiondescribed above, the composition further comprises an untreated,swellable, ion-exchangeable, layered material having nanometer-thickplatelets ranging from about 0.9 nm to about 1000 nm in diameter and anaspect ratio of about 100 to about 1000.

DETAILED DESCRIPTION

The non-halogenated polyamide compositions provided herein exhibitimproved flame retardant properties and arc tracking resistance throughcomparative tracking index (CTI) (class 1 or class 0), as well asexcellent ignition results (Glow wire Ignition Temperature (GWIT) of atleast 775° C.) rendering them suitable for electrical appliances andelectronics components, as well as appliance and transportationapplications. Not wishing to be bound by theory, but it is believed thatthe aromatic polymer acts as a char former, providing the good GWITresults, while at the same time providing excellent mechanicalproperties, impact resistance, and electrical performance.

It was surprisingly found that the combination of the polyamide, flameretardant system and one of more aromatic compounds selected from thegroup consisting of poly(arylene ether), polyetherimide,polyetherimide/polyimide copolymers, poly(arylene sulfide), polysulfone,polyethersulfone, polyetheretherketone, and a SMA impact modifier,resulted in a composition exhibiting a minimum GWIT of 775° C. It wassurprising as other aromatic-based polymers, like polycarbonate andpolyethylene terephthalate, do not yield the desired GWIT results.

The terms “a” and “an” herein do not denote a limitation of quantity,but rather denote the presence of at least one of the referenced item.All ranges disclosed herein are inclusive and combinable.

The polyamide resins include a generic family of resins known as nylons,characterized by the presence of an amide group (—C(O)NH—). Anyamide-containing polymers can be employed, individually or incombination: Nylon-6 and nylon-6,6 are suitable polyamide resinsavailable from a variety of commercial sources. Other polyamides,however, such as nylon-4, nylon-4,6 (PA 46), nylon-12, nylon-6,10,nylon-6,9, nylon-6,12, nylon-9T, copolymer of nylon-6,6 and nylon-6,nylon 610 (PA610), nylon 11 (PA11), nylon 12 (PA 12), nylon 6-3-T (PA6-3-T), polyarylamid (PA MXD 6), polyphthalamide (PPA) and/orpoly-ether-block amide, and others such as the amorphous nylons, mayalso be useful. Mixtures of various polyamides, as well as variouspolyamide copolymers, are also useful.

The polyamides can be obtained by a number of well-known processes suchas those described in U.S. Pat. Nos. 2,071,250; 2,071,251; 2,130,523;2,130,948; 2,241,322; 2,312,966; and 2,512,606. Nylon-6, for example, isa polymerization product of caprolactam. Nylon-6,6 is a condensationproduct of adipic acid and 1,6-diaminohexane. Likewise, nylon 4,6 is acondensation product between adipic acid and 1,4-diaminobutane. Besidesadipic acid, other useful diacids for the preparation of nylons includeazelaic acid, sebacic acid, dodecane diacid, as well as terephthalic andisophthalic acids, and the like. Other useful diamines include m-xylyenediamine, di-(4-aminophenyl)methane, di-(4-aminocyclohexyl )methane;2,2-di-(4-aminophenyl)propane, 2,2-di-(4-aminocyclohexyl)propane, amongothers. Copolymers of caprolactam with diacids and diamines are alsouseful.

It is also to be understood that the use of the term “polyamides” hereinis intended to include the toughened or super tough polyamides. Supertough polyamides, or super tough nylons, as they are more commonlyknown, such as those available commercially, e.g. from E.I. duPont underthe trade name ZYTEL ST, or those prepared in accordance with U.S. Pat.No. 4,174,358 to Epstein; U.S. Pat. No. 4,474,927 to Novak; U.S. Pat.No. 4,346,194 to Roura; and U.S. Pat. No. 4,251,644 to Jeffrion, amongothers and combinations comprising at least one of the foregoing, can beemployed.

Generally, these super tough nylons are prepared by blending one or morepolyamides with one or more polymeric or copolymeric elastomerictoughening agents. Suitable toughening agents are disclosed in theabove-identified U.S. patents as well as in U.S. Pat. No. 3,884,882 toCaywood, Jr., U.S. Pat. No. 4,147,740 to Swiger et al.; and “Preparationand Reactions of Epoxy-Modified Polyethylene”, J. Appl. Poly. Sci., V27, pp. 425-437 (1982). Typically, these elastomeric polymers andcopolymers may be straight chain or branched as well as graft polymersand copolymers, including core-shell graft copolymers, and arecharacterized as having incorporated therein either by copolymerizationor by grafting on the preformed polymer, a monomer having functionaland/or active or highly polar groupings capable of interacting with oradhering to the polyamide matrix so as to enhance the toughness of thepolyamide polymer.

The amount of polyamide present in the composition may be about 30 toabout 96 weight percent, more specifically about 40 to about 80 weightpercent, even more specifically about 50 to about 75 weight percent, oryet more specifically about 60 to about 70 weight percent based on thetotal weight of the composition.

The composition further comprises a flame retardant system, wherein theflame retardant system comprises phosphinates and/or diphosphinates.Suitable phosphinates and phosphinates include, for example a) aphosphinate of the formula (I), a diphosphinate of the formula (II),polymers of the foregoing, or a combination thereof

wherein R¹ and R² are each independently hydrogen, a linear or branchedC₁-C₆ alkyl radical, or aryl radical; R³ is a linear or branched C₁-C₁₀alkylene, arylene, alkylarylene, or arylalkylene radical; M is calcium,aluminum, magnesium, strontium, barium, or zinc; m is 2 or 3; n is 1 or3; and x is 1 or 2; and b) at least one nitrogen compound selected fromthe group consisting of condensation products of melamine and/orreaction products of condensation products of melamine with phosphoricacid, and/or mixtures thereof, including for example melam, melem,melon, melamine cyanurate, melamine phosphate compounds, dimelaminephosphate and/or melamine pyrophosphate, benzoguanamine compounds,terepthalic ester compounds of tris(hydroxyethyl)isocyanurate, allantoincompounds, glycoluril compounds, ammeline, ammelide, and combinationsthereof.

“Phosphinic salt” as used herein includes salts of phosphinic anddiphosphinic acids and polymers thereof. Exemplary phosphinic acids as aconstituent of the phosphinic salts include dimethylphosphinic acid,ethylmethylphosphinic acid, diethylphosphinic acid,methyl-n-propylphosphinic acid, methanedi(methylphosphinic acid),benzene-1,4-(dimethylphosphinic acid), methylphenylphosphinic acid anddiphenylphosphinic acid. The salts of the phosphinic acids of theinvention can be prepared by known methods that are described in U.S.Pat. Nos. 5,780,534 and 6,013,707 to Kleiner et al.

Suitable nitrogen compounds include those of the formula (III) to (VIII)or combinations thereof

wherein R⁴, R⁵, and R⁶ are independently hydrogen, hydroxy, amino, ormono- or diC₁-C₈alkyl amino; or C₁-C₈alkyl, C₅-C₁₆cycloalkyl,-alkylcycloalkyl, wherein each may be substituted by a hydroxyl or aC₁-C₄hydroxyalkyl, C₂-C₈alkenyl, C₁-C₈alkoxy, -acyl, -acyloxy,C₆-C₁₂aryl, —OR⁴ and —N(R⁴)R⁵; or are N-alicyclic or N-aromatic, whereN-alicyclic denotes cyclic nitrogen containing compounds such aspyrrolidine, piperidine, imidazolidine, piperazine, and the like, andNaromatic denotes nitrogen containing heteroaromatic ring compounds suchas pyrrole, pyridine, imidazole, pyrazine, and the like; R⁷, R⁸, R⁹, R¹⁰and R¹¹ are independently hydrogen, C₁-C₈alkyl, C₅-C₁₆cycloalkyl or-alkyl(cycloalkyl), each may be substituted by a hydroxyl or aC₁-C₄hydroxyalkyl, C₂-C₈alkenyl, C₁-C₈alkoxy, -acyl, -acyloxy,C₆-C₁₂aryl, and —O—R⁴; X is phosphoric acid or pyrophosphoric acid; q is1, 2, 3, or 4; and bis 1, 2, 3, or 4.

Exemplary nitrogen compounds include melamine phosphate, melamine,pyrophosphate, melamine polyphosphate, and the like.

The amount of flame retardant system present in the composition may beabout 5 to about 25 weight percent based on the total weight of thecomposition, more specifically about 10 to about 20, and yet morespecifically about 12 to about 15 weight percent.

The composition further comprises an aromatic polymer including, forexample, poly(arylene ether), polyetherimide, poly(arylene sulfide),polysulfone, polyethersulfone, polyetheretherketone, styrenic impactmodifiers, and the like, or a combination comprising at least one of theforegoing aromatic polymers. The aromatic polymer may be present in thecomposition in an amount of about 1 to about 50 weight percent,specifically about 2 to about 40 weight percent, more specifically about2.5 to about 30 weight percent, and yet more specifically about 5 toabout 20 weight percent based on the total weight of the composition.

In one embodiment, the aromatic polymer of the composition comprises apoly(arylene ether). The term poly(arylene ether) includes polyphenyleneether (PPE) and poly(arylene ether) copolymers; graft copolymers;poly(arylene ether) ether ionomers; and block copolymers of alkenylaromatic compounds, vinyl aromatic compounds, and poly(arylene ether),and the like; and combinations comprising at least one of the foregoing;and the like. Poly(arylene ether)s per se, are known polymers comprisinga plurality of structural units of the formula (IX):

wherein for each structural unit, each Q¹ is independently halogen,primary or secondary lower alkyl (e.g., alkyl containing up to 7 carbonatoms), phenyl, haloalkyl, aminoalkyl, hydrocarbonoxy, orhalohydrocarbonoxy wherein at least two carbon atoms separate thehalogen and oxygen atoms, or the like; and each Q² is independentlyhydrogen, halogen, primary or secondary lower alkyl, phenyl, haloalkyl,hydrocarbonoxy, or halohydrocarbonoxy wherein at least two carbon atomsseparate the halogen and oxygen atoms, or the like. It will beunderstood that the term “haloalkyl” includes alkyl groups substitutedwith one or more halogen atoms, including partially and fullyhalogenated alkyl groups. Preferably, each Q¹ is alkyl or phenyl,especially C₁₄ alkyl, and each Q² is hydrogen or C₁₄ alkyl.

Both homopolymer and copolymer poly(arylene ether) are included. Thepreferred homopolymers are those containing 2,6-dimethylphenylene etherunits. Suitable copolymers include random copolymers containing, forexample, such units in combination with 2,3,6-trimethyl-1,4-phenyleneether iunits or copolymers derived from copolymerization of2,6-dimethylphenol with 2,3,6-trimethylphenol. Also included arepoly(arylene ether) containing moieties prepared by grafting vinylmonomers or polymers such as polystyrenes, as well as coupledpoly(arylene ether) in which coupling agents such as low molecularweight polycarbonates, quinones, heterocycles and formals undergoreaction in known mainer with the hydroxy groups of two poly(aryleneether) chains to produce a higher molecular weight polymer. Poly(aryleneether)s further include combinations comprising at least one of theabove. Preferred poly(arylene ether)s are poly(2,6-dimethylphenyleneether) and poly(2,6-dimethylphenylene ether-co-2,3,6-trimethylphenyleneether) such as those described in U.S. Pat. No. 6,407,200 to Singh etal. and U.S. Pat. No. 6,437,084 to Birsak et al.

Suitable poly(arylene ether)s include, but are not limited to,poly(2,6-dimethyl-1,4-phenylene ether);poly(2,3,6-trimethyl-1,4-phenylene) ether;poly(2,6-diethyl-1,4-phenylene) ether;poly(2-methyl-6-propyl-1,4-phenylene) ether;poly(2,6-dipropyl-1,4-phenylene) ether;poly(2-ethyl-6-propyl-1,4-phenylene)ether;poly(2,6-dilauryl-1,4-phenylene) ether; poly(2,6-diphenyl-1,4-phenylene)ether; poly(2,6-dimethoxy-1,4 phenylene) ether;poly(2,6-diethoxy-1,4-phenylene) ether;poly(2-methoxy-6-ethoxy-1,4-phenylene) ether;poly(2-ethyl-6-stearyloxy-1,4-phenylene) ether;poly(2,6-dichloro-1,4-phenylene) ether;poly(2-methyl-6-phenyl-1,4-phenylene) ether;poly(2-ethoxy-1,4-phenylene) ether; poly(2-chloro-1,4-phenylene) ether;poly(2,6-dibromo-1,4-phenylene) ether;poly(3-bromo-2,6-dimethyl-1,4-phenylene) ether; or a mixture of theforegoing poly(arylene ether)s.

In one embodiment where the composition comprises polyamide andpoly(arylene ether), the composition may further comprise acompatibilizing agent to improve the physical properties of thepoly(arylene ether)-polyamide resin blend, as well as to enable the useof a greater proportion of the polyamide component. When used herein,the expression “compatibilizing agent” refers to those polyfunctionalcompounds which interact with the poly(arylene ether), the polyamide,or, preferably, both. This interaction may be chemical (e.g. grafting)or physical (e.g. affecting the surface characteristics of the dispersedphases). hi either case the resulting poly(arylene ether)-polyamidecomposition appears to exhibit improved compatibility, particularly asevidenced by enhanced impact strength, mold knit line strength and/orelongation. As used herein, the expression “compatibilized poly(aryleneether)-polyamide base resin” refers to those compositions which havebeen physically or chemically compatibilized with an agent as discussedabove, as well as those compositions which are physically compatiblewithout such agents, as taught, for example, in U.S. Pat. No. 3,379,792.

Suitable compatibilizing agents include, for example, liquid dienepolymers, epoxy compounds, oxidized polyolefin wax, quinones,organosilane compounds, polyfunctional compounds, and functionalizedpolyphenylene ethers obtained by reacting one or more of the previouslymentioned compatibilizing agents with polyphenylene ether.

The above and other compatibilizing agents are more fully described inU.S. Pat. Nos. 4,315,086; 4,600,741; 4,642,358; 4,826,933; 4,866,14;4,927,894; 4,980,424; 5,041,504; and 5,115,042. The foregoingcompatibilizing agents may be used alone or in various combinations ofone another with another. Furthermore, they may be added directly to themelt blend or pre-reacted with either or both the polyphenylene etherand polyamide, as well as with other resinous materials employed in thepreparation of the compositions of the present invention.

Where the compatibilizing agent is employed in the preparation of thecompositions of the present invention, the initial amount used will bedependent upon the specific compatibilizing agent chosen and thespecific polymeric system to which it is added. Generally, when present,the compatibilizing agent may be present in an amount of about 0.01weight percent to about 25 weight percent, more specifically about 0.4to about 10 weight percent, and more specifically about 1 to about 3weight percent, based on the total weight of the composition.

In yet another embodiment, the aromatic polymer of composition comprisespolyetherimide resins, known compounds whose preparation and propertiesare described in U.S. Pat. Nos. 3,803,085 and 3,905,942.

The polyetherimide used for preparing the blends of this inventioncomprises more than 1, more specifically about 10 to 1000 or more, andyet more specifically about 10 to about 500 structural units, of theformula (X):

wherein T is —O— or a group of the formula —O—Z—O— wherein the divalentbonds of the —O— or the —O—Z—O— group are in the 3,3′, 3, 4′, 4,3′, orthe 4,4′ positions; Z includes, but is not limited to, a divalentradical of formulae (XI):

wherein X includes, but is not limited to, divalent radicals of theformulae (XII):

wherein y is an integer from 1 to about 5, and q is 0 or 1; R includes,but is not limited to, a divalent organic radical: (a) aromatichydrocarbon radicals having from 6 to about 20 carbon atoms, (b)alkylene radicals having from about 2 to about 20 carbon atoms, (c)cycloalkylene radicals having from about 3 to about 20 carbon atoms, and(d) divalent radicals of the general formula (XIII):

where Q includes, but is not limited to, the formulae (XIV):

where y is an integer from about 1 to about 5.

In one embodiment, the polyetherimide may be a copolymer that, inaddition to the etherimide units described above, further containspolyimide structural units of the formula (XV):

wherein R is as previously defined for formula (X) and M includes, butis not limited to, formulae (XVI), (XVII), and (XVIII):

Examples of specific aromatic bis(etlier anhydrides) and organicdiamines are disclosed, for example, in U.S. Pat. Nos. 3,972,902 and4,455,410. Included among the many methods of making the polyetlierimideare those disclosed in U.S. Pat. Nos. 3,847,867, 3,814,869, 3,850,885,3,852,242, 3,855,178, and 3,983,093.

In yet another embodiment, the composition comprises a polyarylenesulfide as the aromatic polymer component. The term polyarylene sulfideincludes polyphenylene sulfide (PPS), polyarylene sulfide ionomers,polyarylene sulfide copolymers, polyarylene sulfide graft copolymers,block copolymers of polyarylene sulfides with alkenyl aromatic compoundsor with vinyl aromatic compounds, and combinations comprising at leastone of the foregoing polyarylene sulfides. Polyarylene sulfides areknown polymers comprising a plurality of structural units of the formula—R—S— wherein R is an aromatic radical such as phenylene, biphenylene,naphthylene, oxydiphenyl, or diphenyl sulfone. Known methods ofpreparing poly(arylene sulfide) include those described in U.S. Pat.Nos. 4,490,522 to Kawabata et al and U.S. Pat. No. 4,837,301 to Glock etal.

Still another embodiment comprises polysulfone or polyether sulfone asthe aromatic polymer component. Polysulfones, polyether sulfones, andpolyarylene ether sulfones are known thermoplastic polymers frequentlyprepared as described in U.S. Pat. Nos. 3,634,355; 4,008,203; 4,108,837;and 4,175,175. A variety of polyaryl ether sulfones are commerciallyavailable, including the polycondensation product of dihydroxydiphenylsulfone with dichlorodiphenyl sulfone and known as polyether sulfone(PES) resin, and the polymer of bisphenol-A and dichlorodiphenyl sulfoneknown in the art as polysulfone (PSF) resin. A variety of PEScopolymers, for example comprising Bisphenol A moieties and diphenylsulfone moieties in molar ratios other than 1:1, may also be found.

Yet another embodiment includes polyetheretherketone as the aromaticpolymer component of the composition. Polyetheretherketone polymers areknown polymers generally having the following structure

wherein Ar includes an aryl group such as phenyl, including, forexample, poly(oxy-p-phenyleneoxy-p-phenylenecarbonyl-p-phenylene.

In yet another embodiment, the aromatic polymer comprises styrenicimpact modifiers. Exemplary styrenic impact modifiers include styreneblock copolymers including styrene-butadiene-styrene copolymer (SBS),styrene-(ethylene-butene)-styrene (SEBS), styrene butadiene rubbers(SBR), acrylonitrile-butadiene-styrene copolymers (ABS), styrene-maleicanhydride (SMA) copolymers, alkyl methacrylate styrene acrylonitrile(AMSAN), methyllmetlhacrylate-butadiene-styrene (MBS), combinationscomprising at least one of the foregoing impact modifiers, and the like.Other suitable impact modifiers includestyreno-(ethylene-propylene)-styrene (SEPS), styrene-(ethylene-butene)(SEB), styrene-(ethylene-propylene) (SEP), styrene-isoprene-styrene(SIS), styrene-isoprene, styrene-butadiene,α-methylstyrene-isoprene-α-methylstyrene,α-methylstyrene-butadiene-α-methylstyrene, as well as hydrogenatedversions. The styrene block copolymers may be the linear or radial type,and the di-block or tri-block type. Commercially available styrene blockcopolymers include KRATON available from Shell and K-RESIN availablefrom Chevron Phillips Chemical Company.

In one embodiment, wherein the composition does not contain an aromaticpolymer selected from the group consisting of poly(arylene ether),polyetherimide, poly(arylene sulfide), polysulfone, polyethersulfone,and polyetheretherketone, the composition comprises an SMA impactmodifier, or a blend of SMA and an additional impact modifier, forexample SEBS.

In another embodiment, the composition comprises an aromatic polymer andan impact modifier. When the composition comprises an impact modifierseparate from the aromatic polymer, the amount of impact modifierpresent in the composition may be about 0 to about 20 weight percent,more specifically about 5 to about 15 weight percent, or even morespecifically about 8 to about 10 weight percent based on the totalweight of the composition.

In one embodiment, the composition may optionally further compriseuntreated, swellable, ion-exchangeable, layered material havingnanometer-thick platelets ranging from about 0.9 nm to about 1000 nm indiameter and an aspect ratio of about 100 to about 1000, thatsufficiently sorb the polymer composition to increase the interlayerspacing between adjacent platelets of the layered material to at leastabout 10 Angstroms (when the material is measured dry) may be used. Theterm ion-exchangeable refers to compounds having a crystal structure inwhich the surfaces thereof are laminated, for instance, by ionic bond,in parallel to each other to form the crystal structure. Examplesinclude nanoclay, colloidal clay, or organophilic clay.

While the term “clay” or “nanoclay” or clay minerals will be usedherein, another description would be “intercalated phyllosilicate” or“intercalated layered silicate.” This description refers to a collectionof fine and hydrous silicate minerals, and when an appropriate quantityof water is added to and the clay is kneaded, the plasticity isgenerated, and when the material is calcinated at a high temperature,sintering occurs. The material used herein can be the natural productsas well as synthesized ones.

In one embodiment, the clay minerals are phylosilicates, including aphylosilicic acid or a phylosilicate. The phylosilicates include, asnatural products, clay minerals in the geological classes of thesmectites, the kaolins, the illites, the chlorites, the attapulgites andthe mixed layer clays. Typical examples of specific clays belonging tothese classes are the smectices, kaoins, illites, chlorites,attapulgites and mixed layer clays. Smectites, for example, includemontmorillonite, bentonite, pyrophyllite, hectorite, saponite,sauconite, nontronite, talc, beidellite, volchonskoite and vermiculite.Kaolins include kaolinite, dickite, nacrite, antigorite, anauxite,halloysite, indellite and chrysotile. Illites include bravaisite,muscovite, paragonite, phlogopite and biotite. Chlorites includecorrensite, penninite, donbassite, sudoite, pennine and clinochlore.Attapulgites include sepiolite and polygorskyte. Mixed layer claysinclude allevardite and vermiculitebiotite.

The synthesized phylosilicates include, for instance, fluorine quadsilicon mica, laponite, smectone. In addition, such ion crystallinecompounds as α-Zr(HPO₄)₂, γ-Zr(HPO₄)₂, α-Ti(HPO₄)₂, and γ-Ti(HPO₄)₂,which are no clay minerals but has the layered crystal structure may beused for this purpose.

The amount of untreated, swellable, ion-exchangeable, layered materialpresent in the composition may be about 0 to about 20 weight percent. Inone embodiment from 2 to 15 weight percent. In another embodiment, from2 to 10 weight percent based on the total weight of the composition.

The composition may optionally further comprise filler, includingfibrous filler and/or low aspect ratio filler. Suitable fibrous fillermay be any conventional filler used in polymeric resins and having anaspect ratio greater than 1. Such fillers may exist in the form ofwhiskers, needles, rods, tubes, strands, elongated platelets, lamellarplatelets, ellipsoids, micro fibers, nanofibers and nanotubes, elongatedfullerenes, and the like. Where such fillers exist in aggregate form, anaggregate having an aspect ratio greater than 1 will also suffice forthe fibrous filler.

Suitable fibrous fillers include, for example, glass fibers, such as E,A, C, ECR, R, S, D, and NE glasses and quartz, and the like may be usedas the reinforcing filler. Other suitable inorganic fibrous fillersinclude those derived from blends comprising at least one of aluminumsilicates, aluminum oxides, magnesium oxides, and calcium sulfatehemihydrate. Also included among fibrous fillers are single crystalfibers or “whiskers” including silicon carbide, alumina, boron carbide,iron, nickel, or copper. Other suitable inorganic fibrous fillersinclude carbon fibers, aramid fibers, stainless steel fibers, metalcoated fibers, and the like.

In addition, organic reinforcing fibrous fillers may also be usedincluding organic polymers capable of forming fibers. Illustrativeexamples of such organic fibrous fillers include poly(ether ketone),polyimide, polybenzoxazole, poly(phenylene sulfide), polycarbonate,aromatic polyamides including aramid, aromatic polyimides orpolyetherimides, polytetrafluoroethylene, acrylic resins, and poly(vinyl alcohol). Such reinforcing fillers may be provided in the form ofmonofilament or multifilament fibers and can be used either alone or incombination with other types of fiber, through, for example, co-weavingor core/sheath, side-by-side orange-type or matrix and fibrilconstructions, or by other methods known to one skilled in the art offiber manufacture.

Non-limiting examples of low aspect fillers include silica powder, suchas fused silica, crystalline silica, natural silica sand, and varioussilane-coated silicas; boron-nitride powder and boron-silicate powders;alkaline earth metal salts; alumina and magnesium oxide (or magnesia);wollastonite, including surface-treated wollastonite; calcium sulfate(as, for example, its anhydride, dihydrate or trihydrate); calciumcarbonates including chalk, limestone, marble and synthetic,precipitated calcium carbonates, generally in the form of a groundparticulate which often comprises 98+% CaCO₃ with the remainder beingother inorganics such as magnesium carbonate, iron oxide andalumino-silicates; surface-treated calcium carbonates; other metalcarbonates, for example magnesium carbonate, beryllium carbonate,strontium carbonate, barium carbonate, and radium carbonate; talc; glasspowders; glass-ceramic powders; clay including calcined clay, forexample kaolin, including hard, soft, calcined kaolin; mica; feldsparand nepheline syenite; salts or esters of orthosilicic acid andcondensation products thereof, silicates including aluminosilicate,calcium silicate, and zirconium silicate; zeolites; quartz; quartzite;perlite; diatomaceous earth; silicon carbide; zinc sulfide; zinc oxide;zinc stannate; zinc hydroxystannate; zinc phosphate; zinc borate;aluminum phosphate; barium titanate; barium ferrite; barium sulfate andheavy spar; particulate aluminum, bronze, zinc, copper and nickel;carbon black, including conductive carbon black; flaked fillers such asglass flakes, flaked silicon carbide, aluminum diboride, aluminumflakes, and steel flakes; and the like. Examples of such fillers wellknown to the art include those described in “Plastic Additives Handbook,4^(th) Edition” R. Gachter and H. Muller (eds.), P. P. Klemchuck (assoc.ed.) Hansen Publishers, New York 1993.

The total amount of filler present in the composition may be about 0 toabout 60 weight percent, more specifically about 5 to about 35 weightpercent, or even more specifically about 10 to about 30 weight percentbased on the total weight of the composition. In one embodiment, theratio of reinforcing filler to non-reinforcing inorganic mineral filleris greater than 1, especially greater than about 1.2, and moreespecially greater than about 1.5.

The composition may optionally further comprise other additives known inthe art. Suitable additives include wear additives, for example,polytetrafluoroethylene (PTFE), molybdenum disulfide (MOS₂), graphite,aramide, carbon fibers, carbon powder, combinations comprising at leastone of the foregoing wear additives, and the like. The amount of wearadditive present in the composition may be about 0 to about 20 weightpercent, more specifically about 1 to about 15 weight percent, or evenmore specifically about 5 to about 10 weight percent based on the totalweight of the composition.

The composition may optionally further comprise a charring catalyst, forexample, a metal salt of a tungstic acid or a complex oxide acid oftungsten and a metalloid, a tin oxide salt such as sodium tin oxide,and/or ammonium sulfamate. Suitable metal salts include alkali metalsalts of a tullgStic acid, such as sodium tungstate. By a complex oxideacid of tungsten and a metalloid is meant a complex oxide acid formed bya metalloid such as phosphorous or silicon and tungsten. Exemplarycomplex oxide acids include silicotungstic acid and phosphotungsticacid. When used, the charring catalyst may be present in an amount of upto about 10 weight percent based on the total weight of the composition,more specifically about 0.1 to about 10 weight percent, and yet morespecifically about 0.1 to about 2 weight percent.

Another optional component of the composition includes a char formersuch as a polyhydric alcohol, for example penterythritol ordipenterythritol; a novolac; vinyl alcohols; starches; etc., asdescribed in U.S. Pat. No. 6,166,114, in an amount of up to about 10weight percent based on the total weight of the composition. In oneembodiment, from 0.1 to about 10 weight percent. In another embodiment,from 0.1 to about 2 weight percent.

Other customary additives may be added to all of the resin compositionsat the time of mixing or molding of the resin in amounts as necessarywhich do not have any deleterious effect on physical properties. Forexample, coloring agents (pigments or dyes), heat-resistant agents,oxidation inhibitors, organic fibrous fillers, weather-proofing agents,lubricants, mold release agents, plasticizer, and fluidity enhancingagents, and the like, may be added.

It should be clear that the invention encompasses reaction products ofthe above-described compositions.

The preparation of the compositions may be achieved by blending theingredients under conditions for the formation of an intimate blend. Allof the ingredients may be added initially to the processing system, orelse certain additives may be precompounded with one or more of theprimary components. When the composition comprises a compatibilizedblend of polyamide and poly(arylene ether), the poly(arylene ether) maybe initially precompounded with impact modifier, optionally with anyother ingredients, prior to compounding with the polyamide resin. Theother ingredients may include some of the polyamide used to prepare thecomposition, while the remaining portion of the polyamide is fed througha port downstream.

The blend may be formed by mixing in single or twin screw type extrudersor similar mixing devices which can apply a shear to the components. Inanother embodiment, long fibers may be blended into the master batch atthe injection molding machine.

In one embodiment, separate extruders are used in the processing of theblend. In another embodiment, the composition is prepared by using asingle extruder having multiple feed ports along its length toaccommodate the addition of the various components. A vacuum may beapplied to the melt through at least one or more vent ports in theextruder to remove volatile impurities in the composition.

In one embodiment, the compatibilized blend of polyamide andpoly(arylene ether) is blended with the flame retardant system andreinforcing filler, such as chopped glass strands, in a Henschel highspeed mixer. Other low shear processes including but not limited to handmixing may also accomplish this blending. The blend is then fed into thethroat of a twin-screw extruder via a hopper. Alternately the glass maybe incorporated into the composition by feeding unchopped strandsdirectly into the extruder. The dispersed glass fibers are reduced inlength as a result of the shearing action on the glass strands in theextruder barrel

In another embodiment, the reinforcing filler, e.g., glass fiber, is notblended in with the flame retardant polymer system, but it isincorporated into the flame-retardant polymer composition by a processknown as pultrusion, which process is described in a number ofreferences, for example, U.S. Pat. Nos. 3,993,726 and 5,213,889. In thepultrusion process, a tow or roving of fibers is pulled through a bathof molten polymer to impregnate the fiber. The impregnated fiber productmay be pulled through a means for consolidating the product such as asizing die. In one embodiment, the impregnated product may be wound onrolls for subsequent use in fabrication processes requiring a continuousproduct. In yet another embodiment, the fiber impregnated by thecomposition of the invention may be chopped into pellets or granules, inwhich the aligned fibers have lengths from 2 mm up to 100 mm. These maybe used in conventional moulding or extrusion processes for formingarticles.

In one embodiment, the compositions are used to prepare molded articlessuch as for example, durable articles, structural products, andelectrical and electronic components, and the like. The compositions maybe converted to articles using common thermoplastic processes such asfilm and sheet extrusion, injection molding, gas-assisted injectionmolding, extrusion molding, compression molding and blow molding. Filmand sheet extrusion processes may include and are not limited to meltcasting, blown film extrusion, and calendaring. Co-extrusion andlamination processes may be employed to form composite multi-layer filmsor sheets. Single or multiple layers of coatings may further be appliedto the single or multilayer substrates to impart additional propertiessuch as scratch resistance, ultra violet light resistance, aestheticappeal, and the like. Coatings may be applied through standardapplication techniques such as rolling, spraying, dipping, brushing, orflow-coating. Film and sheet of the invention may alternatively beprepared by casting a solution or suspension of the composition in asuitable solvent onto a substrate, belt or roll followed by removal ofthe solvent

In one embodiment, the compositions when prepared into 1.6 millimeter(mm) test specimens, exhibit a flammability class rating according toUL-94 of at least V2, more specifically at least VI, and yet morespecifically at least V0.

In yet another embodiment, the composition exhibits a comparativetracking index (CTI) measured according to InternationalElectrotechnical Commission (IEC) standard IEC-60112/3′d using a testspecimen having a thickness of 4.0 mm and a diameter of a minimum of60.0 mm of greater than about 400 Volts, specifically greater than about500 Volts, yet more specifically greater than about 550 Volts, and stillyet more specifically greater than about 600 Volts. A tracking index of400 to 599 Volts corresponds to class 1, and 600 Volts and greater isclass 0.

The compositions described herein have been found to exhibit a Glow WireFlammability Index (GWFI) as measured according to IEC-60695-2-12 of960° C. at a test specimen thickness of about 1.6 mm. Furthermore, thecompositions described herein have been found to exhibit a Glow WireIgnition Temperature (GWIT) as measured according to IEC-60695-2-13 of750° C. or greater at a test specimen thickness of about 1.6 mm, morespecifically greater than about 750° C., and yet more specificallygreater than about 800° C.

It should be clear that compositions and articles made from thecompositions made by the method of this disclosure are within the scopeof the invention. All cited patents, patent applications, and otherreferences are incorporated herein by reference in their entirety.

EXAMPLES

The invention is further illustrated by the following non-limitingexamples. The formulations for the Examples were prepared from thecomponents listed in Table 1 below. TABLE 1 Component Trade NameDescription PA 6 Radipol A24S Polyamide-6 2,4RV PA 66 Radipol A40DPolyamide-66 2,4RV Glass DS1103-10P fiber Melamine Melapur MC25 Flameretardant cyanurate Component Exolit OP1312 Flame retardant systemcontaining A a metal phosphinate and a nitrogen compound available fromClariant PEI Ultem 1010 Polyetherimide PPE pre- Pre-blend of 80.3 weight% blend poly(2,6-dimethylphenylene ether); 18.5 weight percent styrene-butadiene-styrene triblock copolymer; 1.2 weight percent compatibilizer:2-hydroxypropane- 1,2,3-tricarboxylic acid PET PolyethyleneTerephthalate PC Lexan 101 Polycarbonate HIPS High impact polystyreneSEBS Kraton G1657 Impact modifier SEBS-MA Kraton FG1901X Impact modifierSMA Dylark Impact modifier AO1 Irganox 1098 Anti-oxidant AO2 Irgafos 168Anti-oxidant Mold Aluminum stearate release Phyllosil- Dellite 67 G -Nanoclay icate treated Phylosilicate) (Cloisite Na+) from Southern ClayProducts - untreated phylosilicate (Table 6 expt No: 29 & 30) CalcinatedClay

The components were compounded in a corotating twin-screw extruder(Werner & Pfleiderer, type ZSK40), using a screw design having a midrange screw severity, at a melt temperature of 270 to 300° C., and atrates of 45 to 100 kilograms per hour. The resulting resin mixtures werethen molded into bars using typical injection molding machines, rangingfrom laboratory-sized machines to commercial sized machines. Melttemperatures were about 270-300° C., and mold temperature were about50-120° C. The molded bars were then tested according to the testsbelow.

Flammability tests were performed following the procedure ofUnderwriters Laboratories Inc., Bulletin 94 entitled “Tests forFlammability of Plastic Materials for Parts in Devices and Appliances,UL94” of a 0.8 mm and 1.6 mm test piece in the vertical position.According to this procedure, the materials were classified as V-0, V-1,or V-2 on the basis of the test resuIlts.

The tensile modulus and strength were measured by ISO Standard 527/1using a test piece having a thickness of 4.0 mm. Thie units of tensilemodulus is provided in Giga Pascal (GPa) and the units of tensilestrength are provided in Mega Pascal (MPa).

The Izod notched impact was measured according to ISO 180-1A and theresults are provided in units of Kilo Joules per squared meter (KJ/m²).

The comparative tracking index (CTI) was measured according toInternational Electrotechnical Commission (IEC) standardIEC-60112/3^(rd) using a test specimen having a thickness of 4.0 mm anda diameter of a minimum of 60.0 mm. A tracking index of 400 to 599 Voltscorresponds to class 1, and 600 Volts and greater is class 0.

The Glow Wire Flammability Index (GWFI) was measured according toIEC-60695-2-12 using a specimen having a thickness of 1.0 and 1.6 mm anda dimension of 60.0 by 60.0 mm.

The Glow Wire Ignition Temperature (GWIT) was measured according toIEC-60695-2-13 using a specimen having a thickness of 1.0 and 1.6 mm anda dimension of 60.0 by 60.0 mm.

Table 2 contains the results of testing samples of glass fiber filledpolyamide compositions containing the flame retardant system comprisinga phosphinic salt and a nitrogen compound (Component A). N.C. stands fornot classified. TABLE 2 CE1 CE2 CE3 CE4 CE5 CE6 CE7 CE8 CE9 CE10Components PA 6 2,4RV 34.70 29.70 24.70 19.70 35.95 34.70 32.20 29.7028.45 27.20 PA66 2,4RV 34.70 29.70 24.70 19.70 35.95 34.70 32.20 29.7028.45 27.20 Glass Fiber 15.00 25.00 35.00 45.00 25.00 25.00 25.00 25.0025.00 25.00 Component A 15.00 15.00 15.00 15.00 2.50 5.00 10.00 15.0017.50 20.00 AO1 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 AO20.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 Mold release 0.25 0.250.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 Properties Tensile Modulus (GPa)6.8 9.4 12.2 14.1 8.9 8.4 8.9 9.4 9.5 9.7 Tensile Strength (MPa) 112.0140.0 166.5 189.3 161.2 153.5 155.0 140.0 138.0 125.0 Izod notchedimpact (KJ/m²) 7.4 9.5 11.2 12.4 8.7 9.2 8.6 9.5 9.0 7.5 CTI (volts) 600600 600 600 600 600 600 600 600 600 GWFI 960° C. @ 1.0 mm pass pass passpass fail pass pass pass pass pass UL class @ 0.8 mm V2 V2 V0 V0 V2 V2V2 V2 V0 V0 UL class @ 1.6 mm V0 V0 V0 V0 V2 V2 n.c. V0 V0 V0 GWIT @1.0mm 700 675 750 750 fail fail fail 675 700 725 GWIT @ 1.6 mm 725 725 750750 fail fail fail 725 725 725

As illustrated in the Table 2, Comparative Examples 1 to 10 show thatnon-halogenated glass-reinforced polyamide compositions without anaromatic polymer did not meet a GWIT of 775° C.

Table 3 contains the test results of glass fiber filled polyamidecompositions containing the flame retardant system comprising aphosphinic salt and a nitrogen compound, and further comprising anaromatic polymer. TABLE 3 CE11 CE12 CE13 CE14 CE15 CE16 CE17 CE18 CE19CE20 Component PA 6 2,4RV 24.70 19.70 24.70 19.70 24.70 19.70 24.7023.20 20.70 20.70 PA66 2,4RV 24.70 19.70 24.70 19.70 24.70 19.70 24.7023.20 20.70 20.70 Glass fiber 25.00 25.00 25.00 25.00 25.00 25.00 25.0025.00 25.00 25.00 Component A 15.00 15.00 15.00 15.00 15.00 15.00 15.0015.00 15.00 15.00 PEI 10.00 20.00 — — — — — — — — PPE-preblend — — 2.505.00 — — — 13.00 18.00 18.00 PET — — — — — — 10.00 — — — PC — — — —10.00 20.00 — — — — HIPS — — 7.50 15.00 — — — — — — AO1 0.20 0.20 0.200.20 0.20 0.20 0.20 0.20 0.20 0.20 AO2 0.15 0.15 0.15 0.15 0.15 0.150.15 0.15 0.15 0.15 Mold release 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.250.25 0.25 Properties Tensile Modulus (GPa) 9.6 9.9 9.3 9.2 n/a n/a 9.69.4 7.8 8.2 Tensile Strength (MPa) 141.0 141.5 130.4 123.3 n/a n/a 156.8139.4 110.6 121.1 Izod notched impact (KJ/m²) 8.0 7.9 8.7 8.4 n/a n/a8.9 9.2 9.3 9.4 CTI (volts) 425 225 575 550 n/a n/a 575 500 475 475 GWFI960° C. @ 1.0 mm pass pass pass pass pass pass pass pass pass pass ULclass @ 0.8 mm V0 V0 V1 V1 n/a n/a V2 V0 V1 n.c. UL class @ 1.6 mm V0 V0V1 V1 n/a n/a V2 V0 V1 n.c. GWIT @1.0 mm 775 775 775 775 700 725 700 775775 775 GWIT @ 1.6 mm 775 775 775 775 700 725 725 775 775 775

In Table 3, the examples are all based on compositions containing theflame retardant system and an aromatic polymer. Examples 11 to 14,containing PEI and PPE passed GWIT 775° C. Comparative Examples 15-16and 17 contained aromatic polycarbonate and polyethylene terephthalate,respectively. As illustrated by the GWIT results, these aromaticpolymers do not improve the GWIT results of the composition.Additionally, these compositions showed poor flame resistance accordingto UL 94. Example 18 prepared from compatibilized polyamide/PPE blendsmet both GWIT and UL 94 (V0), while at the same time maintainingacceptable mechanical and impact resistance.

Table 4 contains the test results of unfilled polyamide compositionscontaining the flame retardant system and a pre-blend of PPE. TABLE 4CE21 CE22 CE23 CE24 CE25 Components PA 6 2,4RV 44.70 47.20 42.20 36.2024.20 PA66 2,4RV 44.70 47.20 42.20 36.20 24.20 Melamine cyanurate 10.00— — — Component A — 5.00 15.00 15.00 15.00 PPE pre-blend — — — 12.0036.00 AO1 0.20 0.20 0.20 0.20 0.20 AO2 0.15 0.15 0.15 0.15 0.15 Moldrelease 0.25 0.25 0.25 0.25 0.25 Properties Tensile Modulus (GPa) 3.23.2 3.6 2.6 2.5 Tensile Strength (MPa) 72.3 72.3 64.4 90.0 85.0 Izodnotched impact 4.5 4.5 4.4 5.0 5.5 (KJ/m²) CTI (volts) 600 600 600 600550 GWFI 960° C. @ pass pass pass pass pass 1.0 mm UL class @ 0.8 mm V0V2 V2 V2 V1 UL class @ 1.6 mm V0 V2 V0 V2 V0 GWIT @ 1.0 mm (° C.) 750650 675 700 775 GWIT @ 1.6 mm (° C.) 700 650 675 725 800

In Table 4, Comparative Example 21, based on melamine cyanurate, doesnot pass GWIT at the desired temperature. Comparative Examples 22 and 23contain 5 and 15 weight percent of the flame retardant system,respectively, but no aromatic polymer. These examples also do notexhibit the desired GWIT performance. Examples 24 and 25 containing PPEshowed the increased of GWIT as a function of PPE level. Example 25provides excellent flammability and electrical performance, as well asthe desired minimum GWIT of 775° C.

Table 5 provides the results of glass filled compositions containingstyrenic impact modifiers. TABLE 5 CE2 CE9 CE10 CE26 CE27 CE28 ComponentPA 6 2,4RV 29.70 19.70 24.70 29.70 28.45 27.20 PA66 2,4RV 29.70 19.7024.70 29.70 28.45 27.20 Glass fiber 25.00 25.00 25.00 25.00 25.00 25.00Component A 15.00 15.00 15.00 15.00 15.00 15.00 SEBS — — — 10.00 10.00SEBS-MA — — — — 10.00 — SMA — — — — — 3.00 AO1 0.20 0.20 0.20 0.20 0.200.20 AO2 0.15 0.15 0.15 0.15 0.15 0.15 Mold release 0.25 0.25 0.25 0.250.25 0.25 Properties Tensile 9.4 9.5 9.7 7.2 7.8 7.7 Modulus (GPa)Tensile 140.0 138.0 125.0 116.0 117.3 111.5 Strength (MPa) Izod notched9.5 9.0 7.5 11.0 12.8 11.1 impact (KJ/m²) CTI (volts) 600 600 600 600600 600 GWFI 960° C. pass pass pass pass pass pass @ 1.0 mm UL class @V2 V0 V0 V1 V1 n.c. 0.8 mm UL class @ V0 V0 V0 V2 VI V1 1.6 mm GWIT @1.0675 700 725 700 700 775 mm GWIT @ 1.6 725 725 725 725 725 775 mm

As illustrated by Table 5, the compositions containing the flameretardant system and styrenic impact modifiers such as SEBS, SEBSMA, andSMA exhibit excellent impact strength while at the same time maintaininggood CTI, GWFI, and GWIT (except for #28 GWIT in all cases is <775)properties.

Table 6 provides the results of glass filled compositions containinguntreated nanoclay, e.g., high aspect ratio phyllosilicates to lower theamount of flame retardant Component A (as illustrated in Table 1). Thecomposition of Example 30 was developed through a master batch process.In the example, the layered untreated phyllosilicates were dispersed inthe polyamide 6/66 blend matrix. The compounded pellets were next mixedwith component A and other additives and fillers. TABLE 6 CE3 CE11 CE13CE29 CE30 CE31 CE32 CE33 CE34 Component PA 6 2,4RV 24.70 24.70 24.7024.70 22.2 26.5 26.5 30 30 PA66 2,4RV 24.70 24.70 24.70 24.70 22.2 10 1014 14 Glass fiber 35.00 25.00 25.00 31.00 36.00 30 30 30 30 Component A15.00 15.00 15.00 12.00 12.00 16 16 13.5 13.5 PEI 10.00 — — — — — — —PPE-preblend — 2.50 — — 12.5 12.5 6.5 6.5 PET — — — — — — — — PC — — — —— — — — HIPS — 7.50 — — — — — — Calcinated clay — — — — — 3 5 Untreatednanoclay — — — 5 5 3 5 AO1 0.20 0.20 0.20 0.20 0.20 0.2 0.2 0.2 0.2 AO20.15 0.15 0.15 0.15 0.15 0.2 0.2 0.2 0.2 Mold release 0.25 0.25 0.250.25 0.25 0.2 0.2 0.2 0.2 PA 6 powder 1.40 1.40 1.40 1.40 1.40 1.4 1.40.4 0.4 TSAN 0.60 0.60 0.60 0.60 0.60 — — — — Properties Tensile Modulus(GPa) 12.2 9.6 9.3 10.9 12.9 — — — — Tensile Strength (MPa) 166.5 141.0130.4 — — — — — — Izod notched impact (KJ/m²) 11.2 8.0 8.7 — — 6.0 6.05.0 7.0 CTI (volts) 600 425 575 550 600 550 550 550 550 GWFI 960° C. @1.0 mm Pass pass pass pass pass 960 960 960 960 UL class @ 0.8 mm V0 V0V1 V1 V1 UL class @ 1.6 mm V0 V0 V1 V0 V0 V0 V0 V0 V0 GWIT @1.0 mm 750775 775 775 800 750 775 750 775 GWIT @ 1.6 mm 750 775 775 800 800 750775 750 775

As illustrated in Table 6, compositions with untreated nanoclay orcacalcinated clay provide excellent properties in ignition behavior,tracking resistance, flame retardancy and processability as comparedwith compositions containing an aromatic polymer system, i.e., PEI andPPE. The untreated nanoclay compensates for the loss in trackingbehavior or in flame performance due to the presence of PEI and PPE.

1. A flame-retardant polyamide composition, comprising a blend of: apolyamide; about 5 to about 25 weight percent of a flame retardantsystem comprising i) a metal phosphinate or diphosphinate salt; and ii)at least one nitrogen compound selected from the group consisting ofcondensation products of melamine and/or reaction products ofcondensation products of melamine with phosphoric acid, and/or mixturesthereof, including for example melam, melem, melon, melamine cyanurate,melamine phosphate compounds, dimelamine phosphate and/or melaminepyrophosphate, benzoguanamine compounds, terepthalic ester compounds oftris(hydroxyethyl)isocyanurate, allantoin compounds, glycolurilcompounds, ammeline, ammelide, and combinations thereof; and about 1 toabout 50 weight percent of at least one aromatic polymer selected fromthe group consisting of poly(arylene ether), polyetherimide,polyetherimide/polyimide copolymers, poly(arylene sulfide), polysulfone,polyethersulfone, polyetheretherketone, an styrenic impact modifier, andcombinations thereof; wherein all the amounts are based upon the totalweight of the composition.
 2. The composition of claim 1, furthercomprising up to 20 weight percent of an untreated, swellable,ion-exchangeable, layered material having nanometer-thick plateletsranging from about 0.9 nm to about 1000 nm in diameter and an aspectratio of about 100 to about
 1000. 3. The composition of claim 2, wherethe untreated, swellable, ion-exchangeable, layered material is aphylosilicate.
 4. The composition of claim 2, comprising from 2 to 10weight percent of an untreated, swellable, ion-exchangeable, layeredmaterial having nanometer-thick platelets ranging from about 0.9 nm toabout 1000 nm in diameter and an aspect ratio of about 100 to about1000.
 5. The composition of 1, wherein the metal phosphinate salt is ofthe formula (I) and the metal diphosphinate salt is of the formula (II)

wherein R¹ and R² are each independently hydrogen, a linear or branchedC₁-C₆ alkyl radical, or aryl radical; R³ is a linear or branched Cl-C₁₀alkylene, arylene, alkylarylene, or arylalkylene radical; M is calcium,aluminum, magnesium, strontium, barium, or zinc; m is 1, 2 or 3; n is 1or 3; and x is 1 or
 2. 6. The composition of claim 1, wherein thenitrogen compound comprising a compound of the formula (III) to (VIII)or combinations comprising at least one of the foregoing nitrogencompounds

wherein R⁴, R⁵, and R⁶ are independently hydrogen, hydroxy, amino, ormono- or diCi-C₈alkyl amino; or C₁-C₈alkyl, C₅-C₁₆cycloalkyl,-alkylcycloalkyl, wherein each may be substituted by a hydroxyl or aC₁-C₄hydroxyalkyl, C₂-C₈alkenyl, C₁-C₈alkoxy, -acyl, -acyloxy,C₆-C₁₂aryl, —OR⁴ and —N(R⁴)R⁵; or are N-alicyclic or N-aromatic, whereN-alicyclic denotes cyclic nitrogen containing compounds such aspyrrolidine, piperidine, imidazolidine, piperazine, and the like, andN-aromatic denotes nitrogen containing heteroaromatic ring compoundssuch as pyrrole, pyridine, imidazole, pyrazine, and the like; R⁷, R⁸,R⁹, R¹⁰ and R¹¹ are independently hydrogen, C₁-C₈alkyl, C₅-C₁₆cycloalkylor -alkylcycloalkyl, each may be substituted by a hydroxyl or aC₁-C₄hydroxyalkyl, C₂-C₈alkenyl, C₁-C₈alkoxy, -acyl, -acyloxy,C₆-C₁₂aryl, and —O—R⁴; X is phosphoric acid or pyrophosphoric acid; q is1, 2, 3, or 4; and b is 1, 2, 3, or
 4. 7. The composition of claim 1,wherein the polyamide is selected from the group consisting of nylon-6,nylon-6,6, nylon4, nylon-4,6, nylon-12, nylon-6,10, nylon-6,9,nylon-6,12, nylon-9T, copolymer of nylon-6,6 and nylon-6, polyamidecopolymers, polyamide blends, and combinations thereof.
 8. Thecomposition of claim 1, wherein the polyamide is present in an amount ofabout 30 to about 96 weight percent based on the total weight of thecomposition.
 9. The composition of claim 1, wherein the aromatic polymeris compatibilized with the polyamide.
 10. The composition of claim 1,wherein the aromatic polymer is not compatibilized with the polyamide.11. The composition of claim 1, wherein the aromatic polymer ispoly(arylene ether) or polyetherimide.
 12. The composition of claim 1,wherein the aromatic polymer is present in an amount of about 2 to about10 weight percent based on the total weight of the composition.
 13. Thecomposition of claim 1, wherein the aromatic polymer is SMA, or a blendof SMA and SEBS.
 14. The composition of claim 1 further comprising up toabout 30 weight percent of a low-aspect ratio filler.
 15. Thecomposition of claim 11, wherein the low aspect ratio filler is selectedfrom the group consisting of calcinated clay, talc, wollastonite, bariumsulfate, mica, barium titanate, salts or esters of orthosilicic acid,silicates, zeolites, silicas, glass powders, glass-ceramic powders,magnesium hydroxide, hydrotalcites, magnesium carbonates, zinc oxide,zinc stannate, zinchydroxystannate, zinc phosphate, zinc borate, zincsulfide, aluminium phosphate, metal carbonates, and combinationsthereof.
 16. The composition of claim 1 further comprising up to 50weight percent of a fibrous filler.
 17. The composition of claim 1,further comprising up to about 20 weight percent of a wear additivebased on the total weight of the composition, wherein the wear additiveis selected from the group consisting of polytetrafluoroethylene,molybdenum disulfide, graphite, aramide, carbon fiber, carbon powder,and combinations thereof.
 18. The composition of claim 1, wherein thecomposition exhibits a rating of V0 according to UL-94 at 1.6millimeters thickness.
 19. The composition of claim 1, wherein thecomposition exhibits a Glow Wire Flammability Index as measuredaccording to IEC-60695-2-12 of 960° C. or greater at about 1.6millimeter thickness.
 20. The composition of claim 1, wherein thecomposition exhibits a Glow Wire Ignition Temperature as measuredaccording to IEC-60695-2-13 of 750° C. or greater at about 1.6millimeter thickness.
 21. The composition of claim 1, wherein thecomposition exhibits a comparative tracking index measured according toInternational Electrotechnical Commission standard IEC-60112/3^(rd) ofclass 1 or class
 0. 22. An article comprising the composition ofclaim
 1. 23. An article comprising the composition of claim
 2. 24. Thecomposition of claim 2, wherein the composition exhibits a Glow WireFlammability Index as measured according to IEC-60695-2-12 of 960° C. orgreater at about 1.6 millimeter thickness.
 25. The composition of claim1, further comprising up to 50 weight percent of a reinforcing fiber ofbetween 2 and 100 mm in length, wherein the reinforcing fiber is wettedby the blend in a continuous melt pultrusion process so as to give atest piece comprising the composition a tensile modulus strength of atleast 9 GPa.
 26. Pellets which have been obtained by melt homogenizingthe composition of claim 25, extruding the molten product and choppingthe extrudate into pellets.
 24. An article comprising the composition ofclaim 18.